In-vitro susceptibility of salmonellae to antimicrobial agents.

The minimum inhibitory concentrations (MIC) of various antimicrobial drugs, for 667 strains of Salmonella, isolated in three different continents of the world, were determined: 17 antibiotics were tested against 506 randomly selected and 161 chloramphenicol-resistant strains. The activity of the monobactam aztreonam against these organisms was in general equal or superior to that observed with the third-generation cephalosporins, cefotaxime and ceftazidime. Furthermore aztreonam and cefotaxime exhibited uniform and high activity against all the salmonella strains tested, irrespective of their chloramphenicol resistance. Ceftazidime was found to have higher geometric mean MICs only for non-typhi salmonellae from Peru.